P59.24 Genomic Abnormalities in Malignant Pleural Effusion of Lung Cancer Patients Detected by Multiplex Ligation-Dependent Probe Amplification

Abstract

Malignant pleural effusion related to lung cancer (MPE-LC) is a common occurrence in medical practice and its diagnosis is a challenge for clinical laboratories. It is known that most of metastatic tumors to the pleura present chromosomal gains and losses, which can be detected by cytogenomic techniques such as the Multiplex Ligation-dependent Probe Amplification (MLPA). The aim of this study is to evaluate genomic abnormalities in tumor cells from pleural fluid (PF) of patients with lung cancer (LC) by MLPA technique. We evaluated 23 samples of PF: 16 samples from MPE of LC patients (13 with positive cytology, 2 negative and one suspicious) and 7 samples from patients with benign PE (cardiac transudate, parapneumonic and tuberculosis). DNA was extracted using the QIAMP DNA Blood kit (QIAGEN, Valencia, California) and the cytogenomic analysis was performed using the MLPA P175-B1 Tumor Gain kit (MRC-Holland®, Amsterdam, Netherlands), in search of pathogenic CNVs and specific point of BRAF mutations. The results were analyzed with the GeneMarker® software (SoftGenetics, LLC, State Collage, PA). From the 16 cases of MPE-LC, MLPA identified genomic changes in 7 cases with cancer cells in the PF: 1 case with point mutation BRAF (7q34) p.V600E (c.1799T>A) and MDM2 (12q15) duplication; 1 with CDK4 (12q14), MDM2 (12q15) and CCND1 (11q12) duplications (fig 1); 1 with AURKB (17p13) deletion; 1 with AURKB (17p13) deletion and AURKA (20q13), MDM4 (1q32) duplications; 1 with EGFR (7p11), ERBB2 (17q12) and TOP2A (8p12) duplications; 1 with MDM2 (12q15) duplication and 1 case with FGFR1 (8p12) deletion, MDM2 (12q15), CCND2 (12p13) duplications and point mutation BRAF (7q34) p.V600E (c.1799T>A). MLPA analysis of control group showed normal results (fig2). The MLPA technique detected genomic abnormalities in seven MPE-LC samples, when at least 30% of tumor cells were present in the cytological examination. The findings of pathogenic variants in MPE-LC can be valuable to explore new targets for the treatment of lung cancer patients.